This invention relates to a method and an apparatus for recording pictures, or a picture sequence to be more accurate, on a disk-shaped recording medium at least on a picture by picture basis and to a method and an apparatus for reproducing, if partly, the pictures recorded on such a disk-shaped recording medium as well as to such a recording medium. More particularly, the present invention relates to a novel technology of picture management and time code allocation to be used for recording a picture sequence on a disk-shaped recording medium in an editing session.
Time codes normally used in the operation of recording video signals on a tape-shaped recording medium (hereinafter referred to as a tape media) are allocated to frames for one-to-one correspondence in order to make use of the intrinsic property of numbers as identifiers. Thus, any particular picture frame can unequivocally be identified by way of the corresponding time code because this relationship is absolute on the tape. Additionally, the time code assigned to a picture frame remains invariable on the tape media if any editing operations are conducted before and/or after the picture frame unless the picture frame is transferred onto some other tape. Thus, it is possible to specify a number of combinations (events) of an in-point (editing in-point) and an out-point (editing out-point) and carry out that number of editing operations in a single editing session.
FIG. 20 of the accompanying drawings schematically illustrates how a foreign scene is inserted into a picture sequence in an editing operation on a tape media with their time codes invariably accompanying the picture sequence. In FIG. 20, both (a) and (b) show respective picture sequences to be used for an editing operation and (c) in FIG. 20 shows a picture sequence obtained by inserting the picture sequence of (a) of FIG. 20 into the picture sequence (b) of FIG. 20 in the editing operation. Each of the expressions xe2x80x9c00:00:00:00xe2x80x9d and xe2x80x9c00:00:50:00xe2x80x9d in FIG. 20 represents a time code of hour:minute:second:frame. Thus, if the picture sequence (a) of FIG. 20 is laid on a corresponding part of the picture sequence (b) of FIG. 20, the edited picture sequence (c) of FIG. 20 carries the same and identical time codes.
FIG. 21 shows in-points and out-points arranged on a tape media. More specifically, (a) in FIG. 21 shows in-points and out-points arranged on a picture sequence and (b) in FIG. 21 shows a picture sequence obtained by inserting picture sequences, or foreign scenes, into the picture sequence of (a) in FIG. 21 respectively by referring to the in-points and the out-points of(a) in FIG. 21. It may be appreciated that a plurality of combinations (events) of an in-point and an out-point are arranged at a time for an editing session of FIG. 21. More specifically, FIG. 21 shows that a total of three combinations (events) of in-point IN1 and out-point OUT1 through in-point IN3 and out-point OUT3 are specified and the editing operations for the first two combinations (event of in-point IN1 and out-point OUT1 and that of in-point IN2 and out-point OUT2) have been executed. Again, each of the expressions xe2x80x9c00:00: 00:00xe2x80x9d and xe2x80x9c00:00:50:00xe2x80x9d in FIG. 21 represents a time code of hour:minute: second:frame. Thus, if a plurality of events are arranged on the picture sequence (a) of FIG. 21 and foreign scenes are laid on corresponding parts of the picture sequence (a) of FIG. 21, the edited picture sequence (b) of FIG. 20 carries the same and identical time codes. In other words, editing operations can be carried out successfully because the time codes on the tape media remain invariable throughout any editing sessions.
To summarize, the time code system of a tape media has the following functional features.
(1) The picture frames and the time codes have a relationship of one-to-one correspondence on the tape media.
(2) The relationship of (1) is maintained after any editing operations that may be conducted before and/or after a particular picture frame.
(3) The time codes are used to identify particular respective picture frames in editing sessions (not only by the user but also inside the editing equipment).
(4) The time codes notifies the user of the duration of time of picture reproduction from the head of the tape media (so that the remaining time that is available for reproducing picture frames from or recording picture frames on the tape media can be known).
It will be appreciated that the feature of searching out any desired particular picture frames by means of the time codes, or keys, allocated to the picture frames for one-to-one correspondence as described above by referring to a tape media may also be desirable for a disk-shaped medium (hereinafter referred to as a disk media).
On the other hand, the disk media is randomly accessible and hence has the following novel features that are specific to the disk media and not found in the tape media.
Firstly, the conventional tape media is not adapted to cutting out or erasing part of a bit stream of a picture sequence recorded on it. More specifically, it is not adapted to cutting out (or erasing) a particular scene recorded on it and having a certain length and connecting the preceding boundary and the succeeding boundary of the cut out (or erased) particular scene. To the contrary, it is possible to cut out or erase part of a bit stream of a picture sequence recorded on a disk media. If such an editing operation is to be carried out on a tape media, a blank tape and a tape recorder have to be brought in place in advance. Then, all the picture sequence following the particular scene has to be copied on the blank tape and copied back onto the original tape so as to make it directly connect with the end of the scene that immediately preceded the particular scene. It will be appreciated that this is a time consuming tedious operation. FIG. 22 schematically illustrates how a particular scene is cut out from a disk media. In FIG. 22, (a) shows a picture sequence and the shaded area from 00:00:00:00 to 00:00:05:00 represents the particular scene to be cut out. In FIG. 22, (b) shows the picture sequence obtained by cutting out the particular scene of (a) and connecting the preceding boundary and the succeeding boundary of the particular scene. With a disk media to be used for recording pictures, it is easy to cut out part of a picture sequence and connecting the front end and the rear end of the cut out part.
Secondly, with a technique referred to insertion editing used for the tape media, a particular scene is not inserted (in the proper sense of the word) into but laid on the picture sequence already recorded on the tape media. It is in fact an operation not of xe2x80x9cinsertingxe2x80x9d a scene into a picture sequence but of partly xe2x80x9coverlayingxe2x80x9d a picture sequence with a scene. In the case of the disk media, to the contrary, it is possible to realize insertion editing (in the proper sense of the word) that is not an xe2x80x9coverlayingxe2x80x9d operation. In order (not to lay a scene on but) to insert a scene into a picture sequence already recorded on a tape media in an editing operation, a blank tape and a tape recorder have to be brought in place in advance as described above for cutting out a scene. Then, all the picture sequence that is to follow the particular scene to be inserted has to be copied on the blank tape and copied back onto the original tape after the particular scene is laid on the predetermined stretch of the tape so as to make it directly connect with the end of the scene that has been laid on the stretch. It will be appreciated that this is also a time consuming tedious operation.
Thirdly, with the disk media, it is easy to edit by moving part of a picture sequence because the disk media is adapted to cutting out part of a bit stream and inserting a scene (in the proper sense of the word) into a picture sequence without overlaying it with the scene. In other words, the operation of moving a particular scene in a picture sequence in an editing session is an operation of cutting out the scene from the picture sequence and inserting it into some other part of the picture sequence without overlying it with the scene.
To summarize, the disk media has the following functional features that are not found in the tape media.
(A) A bit stream can be partly cut out and erased.
(B) It is possible to realize insertion editing (in the proper sense of the word) without overlaying, if partly, the picture sequence with a scene.
(C) A picture sequence can be partly moved.
On the other hand, when editing a picture sequence on a disk media, utilizing the time code (TC) system of the conventional tape media, the following problems appear.
Firstly, with a disk media where time codes are allocated to the picture frames, the time codes can give rise to a discontinuity when a bit stream thereon is partly cut out or erased by using the functional feature (A) above. Then, if the time codes that are found after the cut out (or erased) particular scene are reallocated to properly indicate the duration of time of picture reproduction from the head of the picture sequence (and remove the discontinuity of the time codes), the time codes will be modified after each editing operation to make it difficult to use them for identifying particular respective picture frames. If the time codes are not reallocated after the editing session, on the other hand, then any particular picture frames will be identified by using the time codes allocated to them respectively but it is no longer possible to tell the duration of time of picture reproduction from the head of the picture sequence because the time codes show discontinuity. In the case of the example of FIG. 22, it will be seen that the time code of 00:00:05:00 of (a) is modified to 00:00:45:00 as indicated by (b). All in all, if the time code system of the conventional tape media is applied to the disk media, the time codes can take only either one of the two roles they play on the tape media of
(i) identifying the particular respective picture frames and
(ii) telling the duration of time of picture reproduction.
Secondly, if the functional feature of (B) is utilized on a disk media for an editing operation of inserting a scene (in the proper sense of the word) into a picture sequence without overlaying the latter with the scene, there arises the problem of how to deal with the time codes for the picture frames of the scene inserted in the editing operation. If, for example, all the time codes are reallocated from the head of the picture sequence after the operation of insertion editing that does not overlay the picture sequence with a foreign scene, the time codes can recover the role of telling the duration of time of picture reproduction. Then, however, a problem will arise when a plurality of events are selected for an editing session as shown in FIG. 23, which illustrates how the relationship between the events and the time codes becomes distorted if the time codes are reallocated after each editing operation, which may be that of insertion editing or cutting out. In FIG. 23, (a) shows that a total of three combinations (events) of in-point IN1 and out-point OUT1 through in-point IN3 and out-point OUT3 are selected and (b) shows that the editing operations for the first two combinations (event of in-point IN1 and out-point OUT1 and that of in-point IN2 and out-point OUT2) have been executed and the time codes have been reallocated. Note that, in the example of FIG. 23, the event of in-point IN1 and out-point OUT1 is used to cut out a scene and the event of in-point IN2 and out-point OUT2 is used to insert a foreign picture sequence. Each of the expressions xe2x80x9c00:00xe2x80x9d, xe2x80x9c35:00xe2x80x9d and xe2x80x9c38:00xe2x80x9d in FIG. 23 represents a time code of hour:minute. Thus, in the example of FIG. 23, as a result of reallocating the time codes after the editing operation using the second event, the third event (in-point IN3 and out-point OUT3) indicates a scene different from the one to be edited. More specifically, the time codes of in-point IN3 and out-point OUT3 of the selected third event are respectively 35:00 and 38:00, which define a stretch of P in (a) of FIG. 23 but the time code of in-point IN3 of the third event will be 40:00 when the time codes are reallocated after the first two editing operations, although the time codes of in-point IN3 and out-point OUT3 of the selected third event remain 35:00 and 38:00, which will then define a stretch that is totally different from the one selected in advance. Thus, while it is possible to realize insertion editing in the proper sense of the word on a disk media, the relationship between the selected events and the time codes will be distorted if the time codes are reallocated from the head after each editing operation in order to recover the role of the disk media of telling the duration of time of picture reproduction. In short, any attempt for providing the disk media with the roles of the time code system of the tape media results in the necessity of reallocating the time codes after each editing operation, which by turn can damage the functional features of the disk media.
Thirdly, since the time codes and the picture frames of a tape media show a relationship of one-to-one correspondence, which is maintained after any editing operations that may be conducted before and/or after a particular picture frame, the picture frames will always be reproduced in the ascending order of the time codes even if part of the picture sequence has been moved. With a disk media, to the contrary, while a picture sequence can be partly moved as pointed out by in (C) above, the picture frames may not necessarily be reproduced in the ascending order of the time codes after moving part of the picture sequence.
Thus, as discussed above, when editing a picture sequence on a disk media by simply applying the time code (TC) system of the conventional tape media, the following problems arise.
(1) The time codes show discontinuity after cutting out or erasing a bit stream.
(2) There arises a problem of reallocating the time codes for the scene inserted by insertion editing (in the proper sense of the word), which is not overlaying the picture sequence, if partly, with the scene.
(3) When a picture sequence is partly moved, the picture frames may not necessarily be reproduced in the ascending order of the time codes to give rise to a problem of how to handle the time codes after moving part of the picture sequence.
In view of the above circumstances, it is therefore the object of the present invention to provide a method and an apparatus for recording a picture sequence on a disk-shaped recording medium and to a method and an apparatus for reproducing, if partly, the picture sequence recorded on such a disk-shaped recording medium as well as to a recording medium to be used for recording a picture sequence that allow picture management and time code allocation to be realized accurately and reliably when editing a picture sequence by utilizing techniques such as cutting out (or erasing) a scene, inserting a scene (in the proper sense of the word) without overlaying the picture sequence with a scene and/or moving part of the picture sequence.
According to an aspect of invention, the above object is achieved by providing a method for recording a picture sequence on a disk-shaped recording medium at least on a picture by picture basis, comprising steps of allocating unique numbers to the pictures on the disk-shaped recording medium for one-to-one correspondence, providing a file of editing information apart from the physical addresses of the substantive data on the disk-shaped recording medium, editing the picture sequence by managing the numbers allocated to the respective pictures for one-to-one correspondence and recording the file of editing information on the disk-shaped recording medium.
According to another aspect of the invention, there is provided an apparatus for recording a picture sequence on a disk-shaped recording medium at least on a picture by picture basis, comprising a number allocation means for allocating unique numbers to the pictures of the disk-shaped recording medium for one-to-one correspondence and a file management means for managing a file of editing information apart from the physical addresses of the substantive data on the disk-shaped recording medium, the picture sequence being edited by managing the numbers allocated to the respective pictures for one-to-one correspondence, the file of editing information being recorded on the disk-shaped recording medium.
According to still another aspect of the invention, there is provided a method for reproducing a picture sequence recorded on a disk-shaped recording medium at least on a picture by picture basis, comprising steps of reading out a file of editing information from the disk-shaped recording medium apart from the physical addresses of the substantive data on the disk-shaped recording medium and reproducing, at least partly, the pictures having respective unique numbers allocated thereto for one-to-one correspondence and managed by using the file of editing information on the basis of the file of editing information.
According to still another aspect of the invention, there is provided an apparatus for reproducing a picture sequence recorded on a disk-shaped recording medium at least on a picture by picture basis, comprising a file reading means for reading out a file of editing information from the disk-shaped recording medium apart from the physical addresses of the substantive data on the disk-shaped recording medium and a reproduction control means for reproducing, at least partly, the pictures having respective unique numbers allocated thereto for one-to-one correspondence and managed by using the file of editing information on the basis of the file of editing information.
According to a further aspect of the invention, there is provided a disk-shaped recording medium for recording a picture sequence at least on a picture by picture basis, adapted to allocating unique numbers to the pictures on the disk-shaped recording medium for one-to-one correspondence, providing a file of editing information apart from the physical addressees of the substantive data on the disk-shaped recording medium and recording video signals edited by managing the unique numbers allocated to said pictures on said file of editing information along with said file of editing information.
Thus, according to the invention, it is now possible to record a picture sequence in a manner that allow picture management and time code allocation to be realized accurately and reliably when editing a picture sequence by utilizing techniques such as cutting out (or erasing) a scene, inserting a scene (in the proper sense of the word) without overlaying the picture sequence with a scene and/or moving part of the picture sequence. The numbers may be combinations of a plurality of numerals to make them hierarchical, serial numbers or any other numbers so long as they are unique relative to each other.